Shoe bottom construction



v Dec. 15; 1942. J A, ROTH SHOE BbT'roM CONSTRUCTION Filed Aug. 18, 1942 IN V EN TOR.

Patented Dec. 15, 1942 SHOE BOTTOM CONSTRUCTION Joseph A. Both, St. Louis, Mo., assignor to Vulcan Corporation Application; August 18, 1942, Serial No. 455,165

Claims.

This invention relates to the construction of a shoe bottom made of light rigid material, such as wood or molded plastic composition material and is particularly directed to means for rendering the shoe bottom partially flexible.

The present invention concerns the construction and incorporation of a highly efiicient flexible joint in the shoe bottom which permits the sole thereof to flex in unison with the foot of the wearer when walking or otherwise exercising the foot. A simple, but effective form of the invention, embodies a single, flexible joint disposed transversely of and substantially at the ball portion of the foot. Two or more of such flexible joints may, however, be utilized, thus increasing the degree of available flexibility.

The shoe bottom may be attached to the upper structure in any suitable manner, such as, by channeling the outer marginal portion of the sole and securing the lower margin of the upper in the channel, as by cementing. The method of attaching the upper to the bottom structure, however, forms no part of the invention and consequently is not illustrated and will not further be described.

In the simplest form of the invention, the shoe bottom is composed of a sole element and a heel, which may be manufactured as an integral unit or the heel may be manufactured separately and attached to the sole. The fore part of the sole is severed transversely at or adjacent to the plane of the ball of the foot dividing the sole into two relatively movable sections. The opposing faces of the sole at the plane of severance are spaced apart a slight distance. A bearing is formed between these opposing faces,

which permits relative movement between the sections of the sole. of inter-engaging male and female cylindrical surfaces. The two sole sections must not only be free to pivot with respect to each other; but they must, also, be held together. To accomplish this, one or more rigid links are provided having their ends pivotally anchored respectively in adjacent portions of the sole sections.

The point of anchorage of the link or links is situated substantially upon a plane intersecting the axis of the hearing. The construction of the anchorage point of the link or links is such that the sections of the sole are permitted freely to move throughout their extended angle of rota- This bearing is composed tion; but when the limit of this angle is reached,

the links then become positive stops of high tensile strength to prevent the accidental rupture of the joint by the application of an abnormal force. To present a better understanding of the invention, particular embodiments thereof will be described and illustrated in the accompanying drawing, in which:

Fig. 1 is a perspective View of a shoe bottom embodying the invention. j

Fig. 2 is a perspective view of the elements of a flexible joint embodying the principles of the invention shown disassembled; but arranged in contiguous relationship.

Fig. 3 is a detail view of a modified form of the invention.

Fig. 4 is a plan view of the fore part of a shoe bottom having a multiple joint. v

Fig. 5 is a detail sectional view showing the construction of the flexible joint.

The shoe bottom may be manufactured in any desiredmanner; such as, by reproduction from a model having the desired size and style characteristics upon a copying lathe; such as, a last turning lathe. The shoe bottom may, howeve'r, be produced by sawing from a suitable wood block on a band saw or by other sawing methods. "It may, also, be produced by molding fromv plastic material.

A preferred general construction for the shoe bottom is to construct the heel 8 as, an integral part with the sole 9. It may be desirable, however, under certain circumstances, to manufacture the sole and heel independently and then secure the heel rigidly to thesole in a subsequent operation.

' Various methods may befollow ed in constructing the flexible joint A satisfactory procedure is, first, to locate the position of the axis about which the sole sections are to rotate. An aperture I 0 is drilled transversely of the sole, substantially parallel to its top face and upon the axis ll of the joint. A pair of anchor-pin-receiving apertures l2 and I3 'are then formed in the sole, one of the apertures being situated forward of the axis H and the other, to the rear thereof. Both of these apertures are situated substantially upon a plane intersecting the axis. A saw cut is then made in a vertical plane upon the axis H, which divides the sole into two sections I4 and I5. Since the saw cut is made centrally of the aperture ill at the axis of the joint, the opposing faces at the plane of severance have substantially similar semicylindrical grooves I8 and I9 formed therein by the execution of the drilling operation. which formed the aperture [0. i I

To complete the pivotal connection between the sections l4 and 15 of the sole, a cylindrical flexible joint.

ward in its chamber.

bearing member 20, of wood or metal, is provided having the same diameter as the drill which formed the grooves l8 and I9. The bearing member 20 is placed in position between the opposing faces l6 and I! and in the grooves l8 and I9. The two sections of the sole are, in this manner, held in accurate alignment and permitted to rotate one upon the other. The width of the saw cut, which divided the two sections, determines the amount of clearance between the faces l6 and I! and thus, also, the degree of maximum angle of flexibility of the joint. The faces l6 and Il may, however, be modified to any de sired extent to'permit greater angular movement between the sections, if that is found necessary.

A rigid link 2|, preferably of metal, is provided to secure the two sections together. The link is provided with apertures 22 and 23 in its end portions. A chamber 24 is formed in the material of the shoe bottom vertically disposed and extending at right angles to the axis ll of the The chamber 24 is situated partially in section It and partially within the section of the sole and is of suflicient length to intersect the apertures l2 and i3 which receive the anchor pins. To look the sections together, the link 2| is placed in its chamber 2& and the pins 25 are driven into the apertures l2 and |3 and through the apertures l2 and i3 and 22 and 23 is such, that, when the pins are driven, the two sections l4 and I5 of the shoe bottom are firmly drawn together.

The apertures 22 and 23 are made slightly larger than the pins 25 to provide for a slight amount of shortening of the distance between the pins when the joint is flexed. Desirably, the chamber 24 does not extend to the bottom face of thesole 9, thus preventing dirt and foreign matter from entering the chamber 24 from below.

It is desirable that the axis H of the flexible joints be situated as close as possible to the top face of the sole. By so doing, the amount of movement of the upper portion of the faces l6 and I! per degree of relative rotation of the sections of the sole is reduced, thereby providing for a substantial degree of flexibilitytherebetween, without creating an excessively large opening between the faces. The link 2| is situated sufiiciently deep in the top of the sole to remain below the surface thereof at all relative positions of the sole sections.

The bearing member 20, preferably, is secured in one of the grooves |8 or H! in order to prevent axial movement thereof. This may be done in any desired manner. In the form of the invention illustrated, the member 20 is made of wood, thus permitting the use of nails 26 to hold it in position. It will be noted, also, that the member 20 is made in two sections disposed respectively on opposite sides of the link 2|.

Fig. 5 of the drawing clearly illustrates the normal relative position of the assembled parts in full lines and, also, in dotted lines, the position of the parts when the toe section M has been flexed upwardly. It will be observed that, as the parts are flexed, the link 2| moves up- The link must, therefore, be movable in the chamber and must be so located that it will notproject above the top face of the sole.

A desirable and modified form of bearing for the flexible joints is illustrated in Fig. 3 wherein semi-cylindrical male and female bearing surfaces 21 and 28 are formed integrally upon the opposing faces 29 and 30 of the sole sections. To construct this type of bearing, the sole of the shoe bottom is first severed by a straight vertical saw out and then the proper contour is given to the opposing faces. They may be shaped by a formed cutter or in any desired manner. In this construction, the length of the shoe bottom, when first produced, must be increased by the radius of the cylindrical surfaces. Thus, the shortening caused by the cutting of the male portion of the bearing will cause the assembled sections to present the correct over-all length.

This type of bearing may, also, be made by constructing each of the sections of the shoe bottom independently. By so doing, each section may be given the correct dimensions to present the required over-all length when assembled.

A multiple joint construction for the shoe bottom is illustrated in Fig. 4. In this construction, thesole is divided into three sections, 3|, 32, and 33, thus requiring two flexible joints. A greater number of sections may, however, be employed, if so desired. In the construction illustrated, the same type of pivot bearings are utilized as heretofore described. Two connecting links serve to connect the sections 32 and 33 and. a single link 35 acts to connect the sections 3| and 32. The link 35 is situated between the two links 33. The adjacent ends of all three links are anchored by a single anchor pin 36. The other ends of the links 34 are anchored by a pin 31, while the remaining end of the link 35 is secured by a pin 38.

It will be apparent to the laymen and shoe stylists alike, that a shoe embodying the present invention, lends itself to modern design to the greatest possible degree. Streamlining and graceful contouring of the shoe bottoms are limited only by the imagination and artfulness of the shoe designer. The mechanism of the jointed sections is almost entirely concealed from view and may be further concealed by inserting plugs within the anchor pin apertures. The plugs may be made of wood or other material matching the material out of which the shoe bottom is made. In addition to the high emciency of the, mechanism, it, also, presents great strength and durability capable of withstanding extremely hard usage.

I claim:

1. An articulated shoe bottom of rigid material comprising a sole extending throughout the length of the shoe, a heel rigid therewith, said sole having, at least, one flexible joint disposed transversely of the fore part of the sole and dividing the sole into sections, said joint having substantially semi-cylindrical inter-engaging bearing surfaces about which the sections of the sole pivot, and, at least, one rigid link acting to hold the sections together, said link having pivots remote from the axis of the joint to permit the link to move with the flexing of the joint and simultaneously hold the sections of the sole firmly together.

2. An articulated shoe bottom of light rigid material comprising a sole and heel, at least one flexible joint disposed transversely of the fore part thereof dividing the sole into sections, said joint having male and female inter-engaging semi-cylindrical surfaces about which the sole sections pivot and at least one rigid link extending transversely of the joint anchored in adjacent sole sections and having pivots remote from and so positioned with respect to the axis of the joint as to permit relative movement of the sections and simultaneously acting to hold the joint together.

3. An articulated shoe bottom of light rigid material comprising a sole and heel, at least one flexible joint disposed transversely of the sole dividing it into sections, said joint having opposing semi-cylindrical grooves, a cylindrical pivot member received in said grooves forming therewith a bearing about which the sole sections pivot and, at least, one rigid metallic link disposed longitudinally of the sole and received in a groove formed in adjacent portions of the sole sections and pins rigidly anchored in the respective sole sections and projecting through enlarged holes in opposite ends of said link, thereby to hold the sole sections together and permit relative movement therebetween.

4. An articulated shoe bottom of light rigid material comprising a sole and heel, at least one flexible joint disposed transversely of the sole, cylindrical male and female inter-engaging surfaces upon the opposing faces of said joint, said faces being spaced apart to permit the joint to flex, a rigid metallic link having holes in its ends and received in aligned recesses formed in adjacent sole sections, a pair of apertures spaced substantially equal distances from the joint axis in the respective coacting jointed sections and lying substantially upon a horizontal plane intersecting the said axis and pins received in said apertures and projecting through the holes in said link whereby said link acts to hold the joint together and permit relative movement between the sole sections.

5. An articulated shoe bottom of rigid material comprising a sole and heel, a plurality of flexible joints disposed transversely of and dividing the fore part of the sole into sections, said joints having inter-engaging male and female semicylindrical bearing surfaces about which the sole sections pivot, a plurality of rigid links extending transversely of and spanning said joints, thereby acting to hold the sections together, said links having an aperture in each end, anchor pins secured in the sole sections and projecting through the apertures in said links, one anchor pin serving to secure adjacent ends of the links of successive flexible joints at all but the extreme front and rear points of anchorage.

JOSEPH A. ROTH. 

